Excel cannot complete this task with available resources??error..C# Automation

Excel cannot complete this task with available resources??error..
choose less data or close appliction...

Exception from HRESULT: 0x800A03EC



public object UploadFiles(string filename,string sheetName)
{


wkb = excel.Workbooks.Open(filename, true, Type.Missing);///////error line




sheet = wkb.Worksheets[sheetName];
colcount = sheet.UsedRange.Columns.Count;
rowcount = sheet.UsedRange.Rows.Count;
Excel.Range range = sheet.Range[sheet.UsedRange.Columns.Address];
datarange = range.Value;
wkb.Close();
excel.Quit();
return datarange;
}